Docker Node.js environment variables

Question

I'm trying to use environment variables on docker only needed for on command. On Mac/Linux I can simple just run token=1234 node command.js and token is available as an environment variable. But when I do this with docker docker exec $CONTAINER nenv token=123 node command.js I get unknown command token=123

possible duplicate of http://stackoverflow.com/questions/27812548/how-do-you-set-an-environment-variable-in-a-running-docker-container — hankchiutw, Apr 05 '16 at 13:27

score 1 · Answer 1 · answered Apr 05 '16 at 13:14

I don't use node env, I recommend to do following:

create config folder

put this in config/index.js

var
    nconf = require('nconf'),
    path = require('path');

nconf.env().argv();

nconf.file('local', path.join(__dirname, 'config.local.json'));
nconf.file(path.join(__dirname, 'config.json'));

module.exports = nconf;

create files: config/config.json (template of config) and config/config.local.json (copy of template with real configuration)

for example:

{
  "app": {
    "useCluster": false,
    "http": {
      "enabled": true,
      "port": 8000,
      "host": "0.0.0.0"
    },
    "https": {
      "enabled": false,
      "port": 443,
      "host": "0.0.0.0",
      "certificate": {
        "key": "server.key",
        "cert": "server.crt"
      }
    },
    "env": "production",
    "profiler": false
  },
  "db": {
    "driver": "mysql",
    "host": "address here",
    "port": 3306,
    "user": "username here",
    "pass": "password here",
    "name": "database name here"
  },
}

use in beginning of Your app: var config = require('./config');

and use config object whenever You need:

var config = require('./config'),
    cluster = require('./components/cluster'),
    http = require('http'),
    ...
    ...
    https = require('https');

cluster.start(function() {
    if (config.get('app:http:enabled')) {
        var httpServer = http.createServer(app);
        httpServer.listen(config.get('app:http:port'), config.get('app:http:host'),
            function () {
                winston.info('App listening at http://%s:%s', config.get('app:http:host'), config.get('app:http:port'));
            });
    }

    if (config.get('app:https:enabled')) {
        var httpsServer = https.createServer({
            key: fs.readFileSync(path.join(__dirname, 'certificates', config.get('app:https:certificate:key'))),
            cert: fs.readFileSync(path.join(__dirname, 'certificates', config.get('app:https:certificate:cert')))
        }, app);
        httpsServer.listen(config.get('app:https:port'), config.get('app:https:host'),
            function () {
                winston.info('App listening at https://%s:%s', config.get('app:https:host'), config.get('app:https:port'));
            });
    }
});

this example is more accurate way to have environment based configs. for example: config.local.json configuration that will be added to .gitignore and so on...

This approach seems like unnecssary work in our use case. We clone our repo into our fresh docker image. So with your approach we would have to create a config file from docker cmd line then run the script — Hillboy, Apr 05 '16 at 13:23
no, just create file config.local.json in docker app, and it will keep configuration, also You can try to modify config/index.js to read configuration from arguments, using node-argument-parser it's good package. — num8er, Apr 05 '16 at 13:28

Sylvain GIROD · Answer 2 · 2016-04-05T13:41:15.633

1

EDIT caused by my stupidness !

You can't set new env var using docker on an existing docker. You have to do this when you build it (using Dockerfile or docker-compose), or when you run it (using docker run $CONTAINER -e "name=value" command).

edited Apr 05 '16 at 13:41

answered Apr 05 '16 at 13:15

Sylvain GIROD

836
1
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score 0 · Answer 3 · answered Feb 13 '17 at 23:03

Even if you need to simply retrieve certain configurations from the command (at docker run time) you can do it simply by switching from node env (process.env) to argv usage.
Such casers are not uncommon (docker-compose), and could be done in very easy way.

npm install yargs --save

run code with docker run or docker exec:

docker exec $CONTAINER node command.j --token 123

then in code:

const argv = require('yargs').argv;
...
let boo = do.something(argv.token);

Docker Node.js environment variables

3 Answers3